ALBANY, N.Y. — New York’s attorney general has begun investigating split-second stock trading by some high-frequency traders and called on the exchanges Tuesday to end the practice he said gives them an unfair advantage.

Attorney General Eric Schneiderman said federal and other state regulators should join in structural reforms.

“Rather than curbing the worst threats posed by high-frequency traders, our markets are becoming too focused on catering to them,” Schneiderman said. He discussed his concerns at a symposium at New York University.

According to the attorney general’s office, advantages include extra computer network bandwidth, ultra-fast connection cables and special high-speed switches to computer servers. Some traders are allowed to place their computer servers within trading venues. The millisecond timing advantages let those traders make “rapid and often risk-free trades before the rest of the market can catch up.”

New York’s attorney general has authority to investigate and prosecute securities fraud under the Martin Act, which the office has used to crack down on widespread institutional issues like research analyst bias. That was a signature case involving other regulators and led by then-Attorney General Eliot Spitzer.

The marketplace has changed radically with technology. State officials say that In the 1960s, people held their stocks for an average of five years, and that has dropped sharply to less than five days, according to one estimate. They also note studies indicating high-frequency traders accounting for about 50 percent of U.S. equity trading volume in 2012.

Schneiderman didn’t name specific traders or exchanges Tuesday.

The New York Stock Exchange declined to comment publicly. NASDAQ officials also declined to comment.

The attorney general last fall reached an agreement for Thomson Reuters to stop selling to high-frequency traders a two-second peek at some market-influencing consumer survey results, followed by agreements last month for several financial firms to stop cooperating with analyst surveys that favored some elite clients. An earlier settlement with BlackRock ended its systematic surveying of Wall Street analysts.

The office has also established a hotline at (800) 771-7755 intended for anyone “who knows of front-running schemes, efforts to trade in illicitly gained confidential information, or firms selling early access to market-moving data.”